Global Positioning System (GPS) has been determined to have problems from time-to-time. In particular, a GPS signal from a satellite can be lost for a variety of reasons. The GPS signal can be lost from jamming and other interferences. More particular, the GPS signal can be lost due to satellite clock failures, poor signal quality, poor installation practices, design flaws, intentional interferences, unintentional interferences, Ionosphere effects, equipment malfunction, signal occultation, and local interference. Since a multitude of devices, users, and networks depend on GPS for timing and location data, a loss of a GPS signal can negatively impact communications.
In an alternate context, when network devices are deployed in a building, using the GPS signal as a synchronization source may be costly or impossible if distribution of the GPS signal is needed. This problem becomes acute as GPS does not penetrate buildings very well. Unlike the problem discussed above in which the GPS signal is lost, the problem here is that the network device cannot receive the GPS signal. For example, network devices, such as enhanced Node Bs (eNodeB), base stations, picocells, or femtocells, can be deployed within a building or residential area, making it difficult for the GPS signal to reach such devices. As a result, a solution is needed that would allow an alternative or backup signal to be provided when network devices are deployed beyond the clear line of sight of a GPS signal, such as in a building. A solution is also needed when the network devices lose the GPS signal even when deployed in clear line of sight of the GPS signal.